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Customs reverse rotation supercharger

Discussion in 'The Hokey Ass Message Board' started by boudin, Jul 14, 2020.

  1. boudin
    Joined: Jan 17, 2018
    Posts: 6


    Is it possible to reverse the rotation of a supercharger ? I e putting a supercharger on a reverse rotation engine and having the blower blow down instead of up.
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 51,150


    put the drive shaft on the other side, it will do the same thing
    badvolvo likes this.
  3. flamedabone
    Joined: Aug 3, 2001
    Posts: 5,051


    Dude, I have to know...what are you getting ready to try??

    squirrel likes this.
  4. Jmountainjr
    Joined: Dec 29, 2006
    Posts: 1,443


    Detroit Diesels are available in both right and left hand rotation. As Squirrel said, just matter of drive location.

  5. boudin
    Joined: Jan 17, 2018
    Posts: 6


    built a reverse rotation 4.3 in a corvair was looking for the wow factor of a supercharger.
    LAROKE and squirrel like this.
  6. dreracecar
    Joined: Aug 27, 2009
    Posts: 3,280

    from so-cal

    Yes it can be done, but will have to send it out to someone like Don Hampton, you have to rotate the front blower cover 180* and swap the gears because of the holes used to attach the drive. What you need him to do is line everything back up and drill oversize dowel pins
  7. Or you can add a pulley and reverse the input.
  8. rooman
    Joined: Sep 20, 2006
    Posts: 4,052


    Not if you are using a toothed belt drive.


    Sent from my iPad using H.A.M.B.
  9. Yes you can.

    I had an extra credit design project last time I was in school and that was the challenge. You can't do it with one belt. Remember all boxes have a way out, it is the same way you got into it.
    Hnstray and VANDENPLAS like this.
  10. Every Detroit 671 blower put on a car has been reversed.
  11. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,307

    from Quincy, IL

    A long time friend of mine owns/operates heavy equipment. One day I was visiting his shop and he had a 6-71 GMC in for repairs. In talking about those engines, he happened to mention that if you want to use it in reverse rotation application you simply take everything off each end of the block and swap it to the opposite end. I didn't ask, but I would surmise that also applies to all the 71 Series engines. GM Engineering of all kinds was among the best in the world for many decades.

  12. boudin
    Joined: Jan 17, 2018
    Posts: 6


    great info. I know that they had a 4.3 supercharged engine ( typhoon maybe ) that used a whipple type possibly a screw typed blower even though the roots style looks cooler in my opinion could this be done on the whipple ?
  13. 19Eddy30
    Joined: Mar 27, 2011
    Posts: 1,480

    from VA

    I would think any Blower / supercharger Company that makes there own parts for 71 series would be able to cut a set of reverse rotor gears with no problems. Setting up a Virgin blower is not that difficult , but do need access to lathe / mill .
    Clarence is no less than about .010 Rotors to rotor ,case & end plates street use
    Loose is better than tight , to loose is like blow bye
    Last edited: Jul 15, 2020

  14. That Typhoon and cyclone was a 4.3 Turbo.
    One of the “auto shows back then did a review on them. “The most impractical vehicles on the planet unless your name is Batman” was the ending opinion. They out performed every single thing available at the time. And who needs to go the grocery store or get the kids to soccer practice that fast anyways.
    3.8 turbo for G body and 3.8 transverse roots super charged for FWD. later the Cadillac with LS motor had supercharger then the others followed.
  15. dreracecar
    Joined: Aug 27, 2009
    Posts: 3,280

    from so-cal


    Its 2 gears meshed together under the cover- How can you "machine" a reverse set of gears??? 1 Rotor turns clockwise and the other turns counter clockwise. Most engines run clockwise so thats the driven rotor, if by some means the motor is run counter clockwise then its the opposite rotor that must be driven
    ottoman likes this.
  16. Actually I have reversed the rotation on a 671 detroit blower. thirty some years ago. These sawmillers had a left hand 6-71 Power unit. The blower went bad and all we could find is a used right hand blower. I had to take it apart and swap the ends to make it fit on the diesel block and the drive be at the correct location. In a custom application it might be possible it simply move the drive like Squirrel suggested????
  17. Not quite that easy. You gotta swap the live cam and the dead cam and turn the head around. You need a different starter. You dont mess with the flywheel or front pulley. The flywheel will only fit on the rear of the crank. I messed with detroit 2 cycle engines since I was a little kid.
    Hnstray likes this.
  18. Wrench97
    Joined: Jan 29, 2020
    Posts: 562


    All Series 71 engines could be made to run left or right, twin engine boats have left and right hand rotation engines.
    For the blowers as stated above it's all in how they are assembled, almost every piece on a 2 stroke Detroit can turned around and mounted the other way.
    Old wolf and Hnstray like this.

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